Squaring device



June 22, 1948. R 'c. FERGUSON 1 2,443,788

SQUARING DEVICE Filed Jan. 5'. 1946 .lnv 13121-01" Fart 2.15011 Patented June 22, 1948 SQUARING DEVICE Ralph-0.. Ferguson; Hollydale; Calif., assignorto l Walter W. Pierce, Whittier, Calif.

Application January 5, 1946, Serial No. 639,378

. 1 My invention relates t-oa fixture designed to be used in the production of precision finished workpieces requiring opposite sides tobe parallel and all angles between the sides to beef:- actly at right angles, the work being intended to be as a gauge" block or for any other purpose requiringthe" use of a very accurately machined block.

Precision machining of such workpieces can" be done by the use of existing techniques only with the expenditure of considerable time andlabor, using a face plate and angle plate in addition to the bed of the machine used; usually a precision grinder.

It is an' object ofthe invention to provide a fixture which enables precision work of the kind described to be produced tofine limits of accuracy of the order of .00001 inch and better with comparativelylittle effort and with avery cOnsidera ble saving of time ascomparedwith present pra'ctice.

Anotherobject of the invention is toprovide a fixture whichis capable of withstanding long continued usewithout requiring it to be refinished to restore its accuracy, the operationsnecessary to refinish the surfaces when this finally becomes necessary being of'a simple nature:

Another object of the invention is to provide a rugged and accurate fixture which is; simple and inexpensive to produce;

Further features and objects of the invention will appear in the following description takenin conjunction with the accompanying drawings.

The invention is hereinafter described and illustrated in a preferred form, but it is to be understood that thescop-e of 'the invention is not in any way limited by this illustrative showing but only as indicated by the scope of the' appended claims. v

In the drawings;

Fig; 1 is a side elevation of the flxtureof my invention;

Fig. 2 is abottomplan of the fixture;

Fig. 3- is a perspective View showingwa typical workpiece which may for instance be intended to be used as a gauge block;

Fig. 4 is a view shOWingthe workpiece being set up preliminary to an operation thereon, while held in the fixture; g p

Fig. 5 is a plan view showing the workpiece in position to be groundto a desired line; and

Fig. 6 is a plan view showing the workpiece in position to receive a; final grinding operation.

. Referring" now to Fig: I, a base plate is indicat'ed by the numeral I0, this base plate being,

5 Claims. (Cl. 51-217) 2. accurately machined to pro-vide upper and lower surfaces truly parallel to oneanother, the upper surface it being adapted for use as a face plate. The base plate is provided with a plurality of bores It to receive clamping members; as later de scribed.

Two-cylindrical abutment members l-Zand' M of the same length and diameter are mounted upon the base plate by a-pluralityof headed studs l S passing through bores lfi' in the base plate into threadedbores 88 extending into the cylinders; The upper end faces 22 and 24 of the cylinders are machined to be at right angles to the side surface of" the cylinders while thelower end faces are" machined out to leave peripheral fianges 26 and 28, respectively, which alrecarefully ground to present end surfaces exactly at right angles to the surfaceof the cylinders.

It wi-llbe seen from Fig. 2 that'the base plate m is rectangular in plan although not necessarily so, the cylinders E2 and W being positioned adjacent one edge of the base-plate and spaced: apart from-"one another; The cylinders are ground true and their surfaces may be used as gauging surfaces althoughgauging of the work is unnecessary due to the inherent accuracy of the device and of themethod of its utilization.

Clamps 303' are fitted into approp-riatebores of the plurality of cores [5' formed inthe base plate, to hold the work'in'position; The clampingpieces iiilm 'ay be of a known typeprovided with-abbdy 39a having threadedbores 3 I arranged at spaced points in the length thereof, and threaded sterile 32 fitted in the threaded bores; which stems are screwed against the work W which is backed against the cylinders. v

. While anysuitable means of securelyholcling the cylinders in, vertical position upon thebase plate may be used, ,Ihave found the construction described to be very satisfactory as'itpermits the cylinders,.ifcontinueduse shows wear on thesurface of the cylinder to be released from the base ill and rotated to bring an unworn' surfaceinto operative position,. after which the studs-l fi' may beagain carefully tightened up to holdthe cylinders perfectly perpendicular to the top face of thebalse plate. A

The procedure in producing; an accurately finishe d workpiece is as follows: the workpiece W shown in Fig. 3 is a rectangular block in which opposite faces are indicatedgby the same letter of the alphabet, three contiguous sides being shown by cl, bl and cl, while the sides opposite tothe sidesfshown are indicated by a2; b2 and 021 It is assumed that the-workpiece has=been machined to approximate size and subsequently heat treated to harden it and allowed to cool to room tempera ture.

Sides al and a2 may be ground to be truly parallel in the usual manner by placing them on the bed of the grinder, which may be of a magnetic type in which the magnetic action of a current flowing through windings in the appropriately' formed bed of the machine securely retains the workpiece in position. The grinding wheel is passed over the upper face al, the

current switched off and workpiece turned over to bring the opposite side a2 under the grinder and the grinding operation repeated. It may, however, be preferred to finish one face al only, in which case the subsequent steps to be described would be slightly varied. For greater accuracy it is desirable to lap the face al withwhich face operations are commenced.

The remaining operations to bring the remaining four sides of the block into parallelism and to be accurately at right angles to the adjacent sides may be carried out in the fixture of my invention with ease and rapidity, whereas according to the usual shop practice it would be necessary to repeatedly remove the piece to a face plate and angle plate for checking and determining the line to which the next out should be taken for the next face to be ground.

These repeated operations on the face plate are a very decided disadvantage. Face plates are expensive equipment and most machine shops are provided with only one. Since they are in constant use by'the machinists, it is very desirable-to. reduce the number of operations requiring the use of the face plate.

It is also very difiicult to obtain absolute accuracy by carrying out the usual procedure in view of the numerous times the workpiece has to be set up and then ground. By the use of my fixture all operations after the first step of bringing one side to a finish or two sides into parallelism may be carried out on my fixture.

Fig. 4 shows the step of setting the line for the first of the second pair of faces. Finished face al is laid against the surface of the cylinders 22 and Z4 and clamped thereagainst by use of the clamp 30 and threaded stem 32 shown in Fig.

1. A comparator 34, previously set, is then stood on the-base of .the fixture to enable the line to which grinding is to be carried to be determined. The work can then be clamped in position by the use of two of the clamps 30 and the fixture placed on the bed of the grinding machine to grind the second face bl.

It is next preferable 'to grind a third face cl to be at right angles to the sides al and bl. To do this the workpiece is placed with a face 0.! against one of the cylinders and face bl against the other cylinder, and i held in this position as shown in Fig.6 by a pair of clamps, each hearing against the workpiece in line with the center of the cylinder supporting the face of the workpiece opposite to that engaged by the clamp. The comparator is .then used to indicate the line to which. grinding of the third face is to be carried, the comparator removed and the face ground. This operation will provide three contiguous surfaces on the workpiece which will be accurately at right angles to one another. The remaining three sides of the workpiece can then be brought into parallelism with the sides already ground by the use of the face plate of the face l0.

Inview of the extreme accuracy desired which, as before mentioned, may be upwardly of.100,000th part of an inch, the face plate is preferably first carefully cleaned, a number of parallels, which are accurately machined lengths of material, are

placed on the bed and the workpiece brought to the proper height by arrangement of the paralle'ls. The work is clamped with a finished face against the cylinders and a second finished face resting on the parallels and the side opposite the latter is ground,-the operation being repeated until all surfaces are ground. B this procedure a workpiece such as the re'ctangularblock shown, or a cube, may be readily and quickly brought to exact dimensions with each of its opposite sides truly parallel and all contiguous sides accurately at right angles to one another.

It will be obvious that by suitably modifyin the procedure above described work pieces having more than four sides maybe also accurately produced.

If, after long continued use, it is considered advisable to refinish the surfaces of the fixture, a light pass of the grinding wheel will true the face of the base while the cylinders can be ground while rotated in a lathe.

I claim: I

1. A fixture of the class described comprising a base plate having parallel fiat top and bottom surfaces, 3. pair of cylindrical abutment members disposed axially upright o the top surface of the base plate parallel to each other, means for adjustably securing the abutment members on the base plate whereby said abutment members may be adjusted to present a selectedportion of their cylindrical surface for engagement by a workpiece, anupright secured at its bottom end to the base plate and clamp means carried by the upright for clamping a workpiece against the peripheral surfaces of the abutment members.

2. The fixture of claim 1 wherein the endsof each abutment member are at right angles to the periphery thereof.

3. A fixture of the class described comprising a base plate having parallel fiat top and bottom surfaces-and having a plurality of parallel apertures therethrough, a pair of parallel upright cylindrical abutment members each havingparallel tapped holes opening through its bottom end, studs extending through said respective apertures and engaging in said respective tapped holes, said base plate having a plurality of bores therethrough spaced from said parallel apertures and. means for clamping a workpiece against the peripheral surfaces of the abutment members, said last named means comprising a post mountable at its bottom endin selected ones of said bores, said posthaving a transverse tapped hole therethrough and a screw clamp threaded in said tapped vhole for axial adjustment towards and away from the abutment members.

4. A fixture of the class described comprising a base plate having parallel flat top and bottom surfaces, a pair of upright abutment members mounted on said plate at right angles thereto, said plate, having a plurality of bores therethrough spaced from said abutment members, and means for clamping a workpiece against the sides of said abutment members comprising a post mountable at its lower end in a selected bore, said post havin a transverse tapped hole therethrough and a screw clamp threaded in said hole 6 plate at right angles to said bottom surface, said REFERENCES CITED plate having a plurality of bores therethrough spaced from said abutment members, and means g ifig gg fg are of record m the for clamping a work piece against the sides of said abutment members comprising a post 5 ED STA ES PATENTS mountable at its lower end in a selected bore and Number Name Date clampmg means earned by said post ad ustable 1 220 237 SW et a1 Mar 27 1917 for movement in a plane parallel to said bottom 1685899 Andrew u 1928 surface for clamping a Work piece against said 1952206 Hogg 1934 abutment members.

l0 RALPH C. FERGUSON 2,354,970 V01ke1 Aug. 1, 1944 

